About Sports Nutrition

Nutrition is essential for us – more than ever when we play sport. It cannot replace training (unfortunately), but it is a factor that can influence the output (1). To give you a good summary of what is beneficial when it comes to sport, I have compiled this information page.

I will provide some numbers, such as grams of protein, but this is only a guideline. It is not here to tell you exactly what and how much you should eat. The numbers are what science suggests, based on research. However, how much you should eat depends greatly on your weight, how much and what sport you play (2) and what your goal is. When you are highly active, you should be aware of what you need and what is ideal or less ideal. However, I do not think you need to be tracking it. If you eat a healthy and balanced diet, you are already very well covered. On top of that, you can still add some specific supplements, if required (1).

The three macronutrients in our food are (3):

  • Carbohydrates
  • Proteins
  • Fats

All three are important and have their own roles in our bodies. Before going into when and how much of which should be consumed, let us have a look at what functions they have.

Carbohydrates

Carbohydrates are the main source of energy for muscle contraction during sport. Missing carbohydrates are one of the factors limiting a person’s performance (3).
Sugars, starches, and fiber are the three main categories of carbohydrates (4). The best source of carbohydrates for athletes are the starchy ones (1). They are also called complex carbohydrates and contain a greater amount of carbohydrates in comparison to non-starchy ones. Therefore, they also give us more energy (5).

Good sources of starchy carbohydrates include (6):

  • Flours (such as bread, pasta, noodles)
  • Crackers
  • Oats
  • Rice
  • Corn
  • Potatoes

There are both high and low glycemic carbohydrates. Glycemic means the rate of carbohydrate to glucose conversion, which results in a spike in blood sugar levels. A high index would mean a rapid increase and a quick energy boost (3). The glycemic index also varies according to what the carbohydrate is paired with. Adding some protein to a high glycemic carbohydrate will lower its index (1).

Fiber plays a big role here too. It slows down the digestion and lowers the glycemic index. Therefore, choosing the whole grain option over the refined version, for example, will have a lower glycemic index as well, because the fiber has not been removed (1).

High glycemic carbohydrates include (7):

  • White rice
  • Rice cakes
  • White bread
  • Potatoes
  • Most crackers
  • Cakes

Low glycemic carbohydrates include (7):

  • Most fruit and vegetables
  • Beans
  • Pasta
  • Nuts
  • Whole-grain versions (such as bread, brown rice)

Protein

A body’s main building block is protein (3). Amongst other functions, it promotes muscle protein synthesis (2). When athletes do not eat enough protein, there will be a negative nitrogen balance which will lead to slow recovery (8).

Good vegetarian sources of protein include (9):

  • Soy, such as:
    • Tofu
    • Tempeh
    • Edamame
  • Legumes, such as:
    • Lentils
    • Chickpeas
    • Beans, such as kidney or black
  • Seeds, such as:
    • Hemp
    • Chia
  • Nuts, such as:
    • Cashews
    • Almonds
  • Grains, such as:
    • Quinoa
    • Amaranth
    • Oats

Fats

Fats are used in specific body functions, some of which are involved in exercise (8). Plant sources are more ideal than animal sources (1).

Good sources of healthy fats include (10):

  • Nuts, such as:
    • Almonds
    • Cashews
    • Peanuts
  • Seeds, such as:
    • Chia
    • Flax
  • Vegetable oils, such as:
    • Olive
    • Peanut
  • Avocado

Minerals

Minerals are essential for our body and are involved in many bodily processes, for example muscle contraction, heart rhythm, oxygen transport and bone health (11). These functions are even more important during sport and therefore athletes, or active people in general, need the right amount of minerals to function and perform (12).

However, athletes generally need to eat more because of their higher energy expenditure. As a result, the higher amounts of vitamins and minerals required are also satisfied. Nevertheless, this is only the case when a varied diet is consumed. Supplements have not been shown to be necessary or to assist performance. Deficiencies in this area are uncommon, except iron and calcium. These should preferably be treated, if possible, by incorporating foods into the diet that are high in these (12).

Therefore, make sure you eat a varied diet to get all the necessary vitamins and minerals. If you are eating a greater amount of food because of sport, you will most likely not have to worry about the greater micronutrient requirements.

The average diet

The recommended average diet consists of (8):

 % of calories / daygrams / kg of body weight / day
Carbohydrates45 -55%3-5 g
Protein15-20%0.8-1.2 g
Fat25-35%0.5-1.5 g

This diet also covers the needs of someone involved in a basic fitness program (30-40 minutes per day, 3 times per week). However, research does show that a slightly greater amount of protein would be optimal. This would be 1.2-2.0 g/kg/d (8).

The athletes’ diet

For people with a moderate to high volume training, it is necessary to consume greater amounts of carbohydrates. These people should be getting 55-65% of their calories from carbohydrates. The amount of protein for those with moderate training is similar to people with a general fitness program, or maybe even slightly higher for high volume, intense training. This amounts to 1.7-2.2 g/kg/d (8). For endurance exercise, the recommendations are lower than for strength/power exercise (13). The amount of fat is comparable to the normal diet (8).

Pre-exercise nutrition

Your nutrition stores, especially glycogen and hydration stores, should always be full at the beginning of training or competition. However, how much you should eat beforehand depends on how much time is left before the session, how much you weigh and what sport it is. The longer the time until the session, the heavier you are and the more intense the session is, the more you should consume. If you do not have very much time left, you should go for a fast-digesting option, such as fruit or crackers. Fat, fiber, and protein take much longer to digest and therefore the choice should be low in these (2).

For endurance sports, you should consume mainly carbohydrates before training. However, for strength focused sessions you should also include protein, as this may have an anticatabolic effect (2). Anticatabolic means protection of the muscle mass from being broken down (14).

The best plan is to have a full-sized meal 3-4 hours before training, to ensure full digestion. This should be high in carbohydrates, low in fiber, low in fat and include a balanced amount of protein. Another snack shortly before the session completes the ideal pre-exercise nutrition (2).

Whether you consume high or low glycemic carbohydrates before training has no influence on performance (2). However, if it is shortly before training, high may be better because these are easily digested and absorbed. On the other hand, when there is a longer time span until training, low glycemic carbohydrates have enough time to digest (3).

Post-exercise nutrition

The role of food after training or a competition is to recover well and as fast as possible, to be able to perform again during the next session. The energy, fluid and electrolyte stores all need to be restored. If you start to refuel as soon as you finish a session, your body can recover best. Research suggests that this timespan is within 30 minutes of finishing. This is because the blood flow is still high and therefore ideal for glycogen resynthesis. This is done through carbohydrates (2).

However, consuming only carbohydrates after training has been shown to have less effect than if it is combined with protein (15). By adding protein after training, the muscle tissue repair can be improved. This can be especially beneficial after strength training. A three or four to one ratio between carbohydrates and protein is ideal (16). The carbohydrates should preferably be high glycemic, as these are absorbed the fastest. There is no research supporting that sports nutrition supplements show any advantages over whole foods. They might be convenient but often more expensive (2).

 

(1) Zurkirchen, Claudia (2020). Personal interview on the 10.12.2020 with a nutritionist B.Sc. with CAS in sports nutrition, Wetzikon

(2) Zoorob, Roger (2013): Sports Nutrition Needs Before, During and After Exercise.  https://europepmc.org/article/med/23668654 [Accessed 18.11.2020]

(3) Valenta, Rudolf/Dorofeeva Yulia A.(2018): Sport nutrition: The role of macronutrients and minerals in endurance exercises. https://vestnik.astu.org/temp/50f149b6ebf31c91847463db8d785ed7.pdf [Accessed: 18.11.2020]

(4) Gunnars, Kris (2020): Carbohydrates: Whole vs. Refined – Here’s the Difference. https://www.healthline.com/nutrition/good-carbs-bad-carbs [Accessed 18.12.2020]

(5) Coyle, Daisy (2018): Starchy vs. Non-Starchy Vegetables: Food Lists and Nutrition Facts.  https://www.healthline.com/nutrition/starchy-vs-non-starchy-vegetables [Accessed 18.12.2020]

(6) Raman, Ryan (2017): 19 Foods That Are High in Starch. https://www.healthline.com/nutrition/high-starch-foods [Accessed 18.12.2020]

(7) Harvard Health Publishing (2020): A guide to good carbs: The glycemic index. https://www.health.harvard.edu/healthbeat/a-good-guide-to-good-carbs-the-glycemic-index [Accessed 18.12.2020]

(8) Kerksick, Chad M. et al. (2018): ISSN exercise & sports nutrition review update: research and recommendations. https://jissn.biomedcentral.com/articles/10.1186/s12970-018-0242-y [Accessed 18.11.2020]

(9) Petre, Alina (2016): The 17 Best Protein Sources for Vegans and Vegetarians.  https://www.healthline.com/nutrition/protein-for-vegans-vegetarians [Accessed 18.12.2020]

(10) Seitz, Adrienne (2020): Good Fats, Bad Fats, and Heart Disease. https://www.healthline.com/health/heart-disease/good-fats-vs-bad-fats#good-fats [Accessed 18.12.2020]

(11) Williams, Melvin H. (2005): Dietary supplements and sports performance: minerals. https://link.springer.com/article/10.1186/1550-2783-2-1-43 [Accessed 18.11.2020]

(12) Maughan, Ron J. (1999): Role of micronutrients in sports and physical activity. https://academic.oup.com/bmb/article/55/3/683/406219 [Accessed 18.11.2020]

(13) Campbell, Bill et al. (2007): International society of sports nutrition position stand: protein and exercise. https://jissn.biomedcentral.com/articles/10.1186/1550-2783-4-8?optIn=true [Accessed: 18.11.2020]

(14) The Free Dictionary (2011): Anticatabolic. https://medical-dictionary.thefreedictionary.com/anticatabolic [Accessed 24.12.2020]

(15) Hoffman, Jay R. (2007): Protein intake: Effect of timing.  https://journals.lww.com/nsca-scj/Abstract/2007/12000/Protein_Intake__Effect_of_Timing.5.aspx [Accessed 18.11.2020]

(16) Kerksick, Chad (2008): International Society of Sports Nutrition position: Nutrient timing. https://jissn.biomedcentral.com/articles/10.1186/1550-2783-5-17 [Accessed 18.11.2020]